QDeferredPointer: Remove the factory before executing it

Only this way we avoid infinite recursion on cyclic references.

Change-Id: I4d6323a093d17f7d55965dc40f9dc5f1a647df9c
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

2 files changed, 9 insertions, 10 deletions

diff --git a/src/qmlcompiler/qdeferredpointer_p.h b/src/qmlcompiler/qdeferredpointer_p.h
index 07875013fa..b8a06cc13c 100644
--- a/src/qmlcompiler/qdeferredpointer_p.h
+++ b/src/qmlcompiler/qdeferredpointer_p.h
@@ -50,7 +50,6 @@ class QDeferredFactory
 public:
     T create() const;
     bool isValid() const;
-    void clear();
 };
 
 template<typename T>
@@ -79,8 +78,9 @@ public:
     operator QSharedPointer<T>() const
     {
         if (m_factory && m_factory->isValid()) {
-            const_cast<std::remove_const_t<T> &>(*m_data) = m_factory->create();
-            m_factory->clear();
+            Factory localFactory;
+            std::swap(localFactory, *m_factory); // Swap before executing, to avoid recursion
+            const_cast<std::remove_const_t<T> &>(*m_data) = localFactory.create();
         }
         return m_data;
     }
@@ -135,8 +135,10 @@ public:
         if (m_factory) {
             auto factory = m_factory.toStrongRef();
             if (factory->isValid()) {
-                const_cast<std::remove_const_t<T> &>(*(m_data.toStrongRef())) = factory->create();
-                factory->clear();
+                Factory localFactory;
+                std::swap(localFactory, *factory); // Swap before executing, to avoid recursion
+                const_cast<std::remove_const_t<T> &>(*(m_data.toStrongRef()))
+                        = localFactory.create();
             }
         }
         return m_data;
diff --git a/src/qmlcompiler/qqmljsscope_p.h b/src/qmlcompiler/qqmljsscope_p.h
index df7aad840d..90696166e4 100644
--- a/src/qmlcompiler/qqmljsscope_p.h
+++ b/src/qmlcompiler/qqmljsscope_p.h
@@ -60,6 +60,8 @@ template<>
 class QDeferredFactory<QQmlJSScope>
 {
 public:
+    QDeferredFactory() = default;
+
     QDeferredFactory(QQmlJSImporter *importer, const QString &filePath) :
         m_filePath(filePath), m_importer(importer)
     {}
@@ -71,11 +73,6 @@ public:
         return !m_filePath.isEmpty() && m_importer != nullptr;
     }
 
-    void clear() {
-        m_filePath.clear();
-        m_importer = nullptr;
-    }
-
 private:
     QString m_filePath;
     QQmlJSImporter *m_importer = nullptr;